Despite their statuses as political outsiders, Trump and Carson have little in common electorally.

Polling data have shown that Carson is attracting evangelical and more religious voters, while Trump's support is demographically broader and a bit firmer. Carson's soft-spoken demeanor also contrasts with Trump's bombast.

But, like Trump, Carson has a penchant for making provocative statements that appear to be benefiting him in the polls.

Two years ago, right as Carson was becoming a nationally known political figure, he opined that the Affordable Care Act, US President Barack Obama's signature health law, was the "worst thing that has happened in the nation since slavery."

While Democrats and others on the left decried the statements, early polling data have shown that conservatives overwhelmingly approve of some of his most controversial comments — and that they are helping him gain traction with the Republican base.

According to a recent Bloomberg/Des Moines Register poll of likely Iowa Republican voters, 80% said that they agreed with his comparison of Obamacare to slavery. Seventy-seven percent said they found his comments on Nazi Germany to be "attractive." And the majority of likely Republican voters said they would not vote for a Muslim president.

Here's a look at Carson's most controversial statements.

On why he believes that people choose to be gay: "A lot of people who go into prison go into prison straight and when they come out, they're gay. So, did something happen while they were in there?" Carson later apologized for the comments.

While watching an Obama speech earlier this year, Carson said that Obama's appearance was emblematic of "most psychopaths. That's why they're successful. That's the way they look. They all look great."

Comparing women who choose to get abortions to slaveowners: "During slavery, a lot of the slaveowners thought that they had the right to do whatever they wanted to that slave. Anything that they chose to do. And, you know, what if the abolitionists had said 'I don't believe in slavery, I think it's wrong, but you guys do whatever you want to do.'"

On why Obamacare is the "worst thing" since slavery: "You know Obamacare is really, I think, the worst thing that has happened in this nation since slavery. It is slavery in a way because it is making all of us subservient to the government."

On how he believes that the AP US history curriculum is too negative: "I think most people, when they finish that course, they'd be ready to go sign up for IS­IS."

On how Hitler could have been stopped by an armed German public: "I think the likelihood of Hitler being able to accomplish his goals would have been greatly diminished if the people had been armed. There's a reason these dictatorial people take the guns first."

On electing a Muslim president: "I would not advocate that we put a Muslim in charge of this nation. I absolutely would not agree with that."

On how political correctness was making American like Nazi Germany: "I mean, [our so­ci­ety is] very much like Nazi Ger­many. And I know you're not sup­posed to say 'Nazi Ger­many,' but I don't care about polit­ic­al cor­rect­ness. You know, you had a government us­ing its tools to in­tim­id­ate the pop­u­la­tion. We now live in a so­ci­ety where people are afraid to say what they ac­tu­ally be­lieve."

On abortion and the black community: "The No. 1 cause of death for black people is abortion."

Writing in The Washington Post, Carson said selfies were narcissistic and dangerous: "Beyond the obvious narcissism of endlessly photographing oneself and blasting it over social networks for others to admire, selfies are dangerous — to animals, sports spectators, artwork and the rest of us."

On one thing that he sees in common between ISIS and the US's Founding Fathers: "They've [IS­IS] got the wrong philosophy, but they're willing to die for what they believe, while we're busily giving away every value and every belief for the sake of political correctness."